Although researchers have related sexual desire in older women to quality-of-life variables such as overall physical health, well-being, and life satisfaction, little is known about the socio-cultural mechanisms that shape sexual desire in minority ethnic older women. We investigated this sexual variable among Mexican-American older women in a qualitative fashion. Data were collected from 25 community-dwelling women of Mexican descent (aged 59-89 years) using a semi-structured interview protocol and a grounded theory approach. We inquired about dimensions of sexual desire including sexual fantasies and the desire to engage in sexual activity within the context of several socio-cultural and health-related factors. Using content analysis, we were able to identify key themes differentiating among respondents' levels of sexual desire and fantasies. These included the availability of a suitable partner, cultural and religious norms pertinent to women's sexuality, stigma related to sexuality in older age, and health status. Traditional socio-cultural restrictions coupled with unmarried status and physical health problems emerged as critical issues associated with limited or no sexual fantasies and desire in our sample. Many respondents indicated that their sexual needs were unmet.